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Search: id:A127357
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| A127357 |
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Expansion of 1/(1-2x+9x^2). |
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+0
2
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| 1, 2, -5, -28, -11, 230, 559, -952, -6935, -5302, 51811, 151340, -163619, -1689298, -1906025, 11391632, 39937489, -22649710, -404736821, -605626252, 2431378885, 10313394038, -1255621889
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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Hankel transform of A100193. A member of the family of sequences with g.f. 1/(1-2x+r^2*x^2) which are the Hankel transforms of the sequences given by sum{k=0..n, C(2n,k)*r^(n-k)}.
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FORMULA
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a(n)=sum{k=0..n, C(n-k,k)2^(n-2k)*(-9)^k}.
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PROGRAM
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(Other) sage: [lucas_number1(n, 2, 9) for n in xrange(1, 24)] # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 23 2009]
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CROSSREFS
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Sequence in context: A058182 A057438 A002795 this_sequence A025170 A151775 A095159
Adjacent sequences: A127354 A127355 A127356 this_sequence A127358 A127359 A127360
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KEYWORD
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sign
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), Jan 11 2007
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